More than 3.8 million shares of the Japan-Vietnam Medical Instrument JSC (JVC) have been sold to meet margin calls as the company's stock has sunk since June 10.

JVC's former CEO Le Van Huong was forced by VPBank Securities Company to reduce his shareholding in the company twice on June 22 and 25 and he has sold over two million shares in total, news website VnExpress reported Friday, citing the Ho Chi Minh City Stock Exchange.

Prior to the sell-off, Huong owned 13.3 million shares or 11.8 percent of the company.

On June 15, Phu Hung Securities Company also sold 1.8 million shares owned by Huong's wife, Nguyen Phuong Hanh.

JVC's stock, once offering a dividend rate of 15-20 percent for several years, started plummeting following rumors that Huong, then its CEO, was arrested.

The company issued a statement on June 13 claiming that everything was normal, but about one week later announced that Huong had been replaced by Kyohei Hosono, representative of Japanese-owned DI Asian Industrial Fund, which owns a 19 percent stake.

Early this week JVC confirmed that Huong had been taken into police's custody for an investigation into his "personal wrongdoings."

Since June 10, JVC's stock has declined by 56 percent from VND21,200 to VND9,300 (97-42 cents), and during the time, at some point, up to 23 million shares, or 20 percent of the company's listed shares, was put up for sale.

JVC had its initial public offering in 2011 with a charter capital of VND242 billion ($11 million), of which Huong owned 55 percent.

The capital has been increased to over VND1.12 trillion ($51.5 million) over the years.